TOKYO • Japan's top court will rule this week on a pair of 19th century family laws that critics blast as sexist and out of touch.

The Supreme Court will weigh in on the legality of a six-month ban on women remarrying after divorce and another law that requires spouses to have the same surname, in a highly anticipated decision set for tomorrow.

The court will decide whether to uphold, amend or strike down the controversial legislation, which dates back to an era of starkly different social mores.

The half-year remarriage ban is linked to complex rules over the timing of a child's birth after divorce - designed to determine whether a child belonged to the former husband or the new spouse's family in an era before DNA testing.

The surname rule is a throwback to the feudal family system, in which all women and children came under the control of the head of the household - traditionally a man.

That system was abolished in 1948, part of broad reforms pushed by the post-World War II US occupation, but Japan's civil code maintained the two articles - which will go before the court this week.

Activists say the laws are a continued reflection of the country's male-dominated society more than a century after they came into effect.

Mother and activist Masae Ido knows first-hand the implications of the half-year ban on remarriage.

"These laws mean a woman remains under a man's sexual control even after divorce," Ms Ido, 50, said.

She vividly recalls her frustration after the birth of a child with her second husband. A municipal official said her former husband must be registered as the father of her baby - who, under the rules, was born too soon after they divorced - even though he was not biologically related to the child.

A long and difficult split left Ms Ido feeling unable to ask the former husband to publicly acknowledge the child as not his, so she had to sue her new spouse in a judicial tango to fix the paternity puzzle.

"My child was finally registered after this bizarre legal procedure," said Ms Ido, now an activist helping those in similar situations.

Prime Minister Shinzo Abe has repeatedly declared his intention to boost the role of women at work as part of his broader bid to kick-start the economy.

AGENCE FRANCE-PRESSE